DC-DC power converters are used to convert an unregulated source of DC power into a source of constant voltage for use in various applications. Some DC power converters include a transformer having primary and secondary windings. A switch can be coupled to the primary winding in order to control energy transfer from the primary to secondary winding. In PWM-controlled converters, the switch can be under the control of a pulse width modulator (PWM) circuit which varies the duty cycle over a switching period. Increasing switching frequency to reduce size and weight, such as required in certain applications, can rapidly increase switching losses. To offset the switching losses, various techniques of soft switching can be employed, such as those which have zero-current or zero voltage switching at turn-on and turn-off transitions, while keeping voltage and current stresses similar those in a PWM (hard-switched) converter. This is so because stress levels for switch voltage and current similar to those in a PWM (hard-switched) converters can provide the best possible efficiency in power transfer.